The exact original boundaries of Paeonia, like the early history of its inhabitants, are obscure, but it is known that it was located immediately north of ancient Macedonia (which corresponded roughly to the modern Greek region of Macedonia), and to the south-east of Dardania (which was similar to modern-day Kosovo); in the east were the Thracian mountains, and in the west, the Illyrians.[2] It was separated from Dardania by the mountains through which the Vardar river passes from the field of Scupi (modern Skopje) to the valley of Bylazora (near modern Sveti Nikole).

Some modern scholars consider the Paionians to have been of either Thracian,[15] or of mixed Thraco-Illyrian origins.[16] Some of the names of the Paionians are also definitely Hellenic (Lycceius, Ariston, Audoleon), although relatively little is known about them.[17] Linguistically, the very small number of surviving words in the Paeonian language have been variously connected to its neighboring languages – Illyrian and Thracian; (and every possible Thraco-Illyrian mix in between).[18] Several eastern Paeonian tribes, including the Agrianes, clearly fell within the Thracian sphere of influence. Yet, according to the national legend,[19] they were Teucrian colonists from Troy. Homer[20] speaks of Paeonians from the Axios fighting on the side of the Trojans, but the Iliad does not mention whether the Paeonians were kin to the Trojans. Homer calls the Paeonian leader Pyraechmes (parentage unknown); later on in the Iliad (Book 21), Homer mentions a second leader, Asteropaeus, son of Pelagon.

Before the reign of Darius Hystaspes, they had made their way as far east as Perinthus in Thrace on the Propontis. At one time all Mygdonia, together with Crestonia, was subject to them. When Xerxes crossed Chalcidice on his way to Therma (later renamed Thessalonica), he is said to have marched through Paeonian territory. They occupied the entire valley of the Axios (Vardar) as far inland as Stobi, the valleys to the east of it as far as the Strymon and the country round Astibus and the river of the same name, with the water of which they anointed their kings. Emathia, roughly the district between the Haliacmon and Axios, was once called Paeonia; and Pieria and Pelagonia were inhabited by Paeonians. As a consequence of the growth of Macedonian power, and under pressure from their Thracian neighbors, their territory was considerably diminished, and in historical times was limited to the north of Macedonia from Illyria to the Strymon.

Subjugation of the Paeonians happened as a part of Persian military operations initiated by Darius the Great (521–486) in 513 – after immense preparations – a huge Achaemenid army invaded the Balkans and tried to defeat the European Scythians roaming to the north of the Danube river.[22] Darius' army subjugated several Thracian peoples, and virtually all other regions that touch the European part of the Black Sea, such as parts of nowadays Bulgaria, Romania, Ukraine, and Russia, before it returned to Asia Minor.[22][23] Darius left in Europe one of his commanders named Megabazus whose task was to accomplish conquests in the Balkans.[22] The Persian troops subjugated gold-rich Thrace, the coastal Greek cities, as well as defeating and conquering the powerful Paeonians.[22][24][25]

At some point after the Greco-Persian Wars, the Paeonian princedoms coalesced into a kingdom centred in the central and upper reaches of the Axios and Strymon rivers, corresponding with today's northern part of North Macedonia and western Bulgaria. They joined with the Illyrians to attack the northern areas of the kingdom of Macedonia. The Illyrians, who had a culture of piracy, would have been cut off from some trade routes if movement through this land had been blocked. They unsuccessfully attacked the northern defences of Macedonian territory in an attempt to occupy the region. In 360–359 BC, southern Paeonian tribes were launching raids into Macedon, (Diodorus XVI. 2.5) in support of an Illyrian invasion.

The Macedonian Royal House was thrown into a state of uncertainty by the death of Perdiccas III, but his brother Philip II assumed the throne, reformed the army (providing phalanxes), and proceeded to stop both the Illyrian invasion and the Paeonian raids through the boundary of the "Macedonian Frontier", which was the northern perimeter which he intended to defend as an area of his domain. He followed Perdiccas's success in 358 BC with a campaign deep into the north, into Paeonia itself.[26][27][28][29][30][31] This reduced the Paeonian kingdom (then ruled by Agis) to a semi-autonomous, subordinate status, which led to a process of gradual and formal Hellenization of the Paeonians, who, during the reign of Philip II, began to issue coins with Greek legends like the Macedonian ones. A Paeonian contingent, led by Ariston, was attached to Alexander the Great's army.

At the time of the Persian invasion, the Paeonians on the lower Strymon had lost, while those in the north maintained, their territorial integrity. The daughter of Audoleon, a king of Paeonia, was the wife of Pyrrhus, king of Epirus, and Alexander the Great wished to bestow the hand of his sister Cynane upon Langarus, king of the Agrianians, who had shown himself loyal to Philip II.

The Paeonians included several independent tribes, all later united under the rule of a single king. Little is known of their manners and customs. They adopted the cult of Dionysus, known amongst them as Dyalus or Dryalus, and Herodotus mentions that the Thracian and Paeonian women offered sacrifice to Queen Artemis (probably Bendis). They worshipped the sun in the form of a small round disk fixed on the top of a pole. A passage in Athenaeus seems to indicate the affinity of their language with Mysian.[citation needed] They drank barley beer and various decoctions made from plants and herbs. The country was rich in gold and a bituminous kind of wood (or stone, which burst into a blaze when in contact with water) called tanrivoc (or tsarivos).

The scanty remains of the Paeonian language do not allow a firm judgement to be made. On one side are Wilhelm Tomaschek and Paul Kretschmer, who claim it belonged to the Illyrian family, and on the other side is Dimitar Dečev, who claims affinities with Thracian. On the other hand, the Paeonian kings issued coins from the time of Philip II of Macedon onwards, bearing their names written in straightforward Greek. All the names of the Paeonian Kings that have come down to us are, in fact, explainable with and clearly related to Greek (Agis, Ariston, Audoleon, Lycceius, etc.), a fact that, according to Irwin L. Merker, puts into question the theories of Illyrian and Thracian connections.

The women were famous for their industry. In this connection Herodotus[51] tells the story that Darius, having seen at Sardis a beautiful Paeonian woman carrying a pitcher on her head, leading a horse to drink, and spinning flax, all at the same time, inquired who she was. Having been informed that she was a Paeonian, he sent instructions to Megabazus, commander in Thrace, to deport two tribes of the nation without delay to Asia. An inscription, discovered in 1877 at Olympia on the base of a statue, states that it was set up by the community of the Paeonians in honor of their king and founder Dropion. Another king, whose name appears as Lyppeius on a fragment of an inscription found at Athens relating to a treaty of alliance, is no doubt identical with the Lycceius or Lycpeius of Paeonian coins.[52]

In 280 BC, the Gallic invaders under Brennus ravaged the land of the Paeonians, who, being further hard pressed by the Dardani, had no alternative but to join the Macedonians. Despite their combined efforts, however, the Paeonians and Macedonians were defeated. Paeonia consolidated again but, in 217 BC, the Macedonian king Philip V of Macedon (220–179 BC), the son of Demetrius II, succeeded in uniting and incorporating into his empire the separate regions of Dassaretia and Paeonia. A mere 70 years later (in 168 BC), Roman legions conquered Macedon in turn, and a new and much larger Roman province bearing this name was formed. Paeonia around the Axios formed the second and third districts respectively of the newly constituted Roman province of Macedonia.[53] Centuries later under Diocletian, Paeonia and Pelagonia formed a province called Macedonia Secunda or Macedonia Salutaris, belonging to the Praetorian prefecture of Illyricum.

^Ovid; Green, Peter (2005). The Poems of Exile. University of California Press, 2005. p. 319. Ovid was lax in his geography, not least over Paeonia (in fact roughly coextensive with the present F.Y.R.O.M.).

^The Landmark Thucydides: A Comprehensive Guide to the Peloponnesian War by Thucydides, Robert B. Strassler, Richard Crawley, and Victor Davis Hanson, 1998, ISBN0-684-82790-5, page 153,"... of them still live round Physcasb- and the Almopians from Almopia.

^The Cambridge Ancient History, Martin Percival Charlesworth, ISBN0-521-85073-8, ISBN978-0-521-85073-5
Volume 4, Persia, Greece and the Western Mediterranean, C. 525 to 479 B.C, John Boardman, page 252, "The Paeonians were the earlier owners of some of these mines, but after their defeat in the coastal sector they maintained their independence in the mainland and coined large denominations in the upper Strymon and the Upper Axius area in the names of the Laeaei and the Derrones"

^An Inventory of Archaic and Classical Poleis: An Investigation Conducted by The Copenhagen Polis Centre for the Danish National Research Foundation by Mogens Herman Hansen and Thomas Heine Nielsen, 2005, ISBN0-19-814099-1, page 854, ... Various tribes have occupied this part of Thrace: Bisaltians (lower Strymon valley), Odomantes (the plain to the north of the Strymon) ...

^Thrace in the Graeco-Roman world, p. 112 but others claim that together with the Agrianes and Odomanti, at least the latter of which were with certainty Thracian, not Paeonian.

^The Histories (Penguin Classics) by Herodotus, John M. Marincola, and Aubery de Selincourt, ISBN0-14-044908-6, 2003, page 315, ... "was that a number of Paeonian tribes – the Siriopaeones, Paeoplae, ..."

^The Histories (Penguin Classics) by Herodotus, John M. Marincola, and Aubery de Selincourt, ISBN0-14-044908-6, 2003, page 452, "... Then he passed through the country of the Doberes and Paeoplae (Paeonian tribes living north of Pangaeum), and continued in a ..."

^The Histories (Penguin Classics) by Herodotus, John M. Marincola, and Aubery de Selincourt, ISBN0-14-044908-6, 2003, page 315, "... was that a number of Paeonian tribes – the Siriopaeones, Paeoplae, ..."

^The History of the Ancient World: From the Earliest Accounts to the Fall of Rome by Susan Wise Bauer (2007), ISBN0-393-05974-X, page 518: "... Italy); to the north, Thracian tribes known collectively as the Paeonians."

^Catalogue of Greek Coins: Thessaly to Aetolia by Percy Gardner, 2004, Front Matter: "... present to the money of Philip II. of Macedon, and Lycceius and Audoleon, kings of Paeonia, that they must be given ..."

^A Guide to the Principal Gold and Silver Coins of the Ancients: From Circ. B. C. 700 to a. D. 1. (1895) by British Museum Dept. of Coins and Medals, 2009, page 62: "... of Athena, facing. Bee. AYAnA EONTOZ. Horse. Wt. 193.4 grs. Patraus and his son Audoleon reigned over Paeonia between B.C. 340 ..."

^ abPolyaenus, Stratagems of War, 4.12.3, "Lysimachus conducted Ariston, son of Autoleon, to his father's kingdom in Paeonia; under pretence that the royal youth might be acknowledged by his subjects, and treated with due respect. But as soon as he had bathed in the royal baths in the river Arisbus, and they had set before him an elegant banquet, according to the custom of his country, Lysimachus ordered his guards to arm. Ariston instantly mounted his horse and escaped to the land of the Dardani; and Lysimachus was left in possession of Paeonia."

^ abcdPausanias, Description of Greece Phocis and Ozolian Locri, 10.13.1, "A bronze head of the Paeonian bull called the bison was sent to Delphi by the Paeonian king Dropion, son of Leon."

^Catalogue of Greek Coins: Thessaly to Aetolia by Percy Gardner, 2004, Front Matter: "...present to the money of Philip II. of Macedon, and Lycceius and Audoleon, kings of Paeonia, that they must be given..."

^A Guide to the Principal Gold and Silver Coins of the Ancients: From Circ. B. C. 700 to a. D. 1. (1895) by British Museum Dept. of Coins and Medals, 2009, page 62: "... Patraus and his son Audoleon reigned over Paaonia between B.C. 340 ..."